Self-cleaning forging die



M y 1954 F. E. DAVIS 2,679,175

SELF-CLEANING FORGING DIE Filed July 31, 1952 Patented May 25, 1954 SELF-CLEANING FORGING DIE Floyd E. Davis, Gary, Ind., assignor to United States Steel Corporation, a corporation of New Jersey Application July 31, 1952, Serial No. 301,917

2 Claims. 1

The present invention relates generally to metal forging and more particularly to a-selfcleaning die especially suitable for forgingrailroad car wheels. In the manufacture of railroad car wheels, the heated wheel blank is removed from the heating furnace and descaled before the initial forging operation. The initial descaling of the wheel blank is very important in the manufacture of quality railroad car wheels. If the descaling is not thorough, particles of scale remaining on the blank will fall 01f into the die cavity during the subsequent forging operation and imbed themselves into the surface of the forged wheel. The presence of these surface defects most generally necessitates the rejection of the railroad wheel after the surface has been machined and pits discovered.

Several types of apparatuses and methods have been devised in an attempt to insure thorough descaling, before forging. However, none of these have been entirely successful. With the best practice devised up to the time of my invention, some particles of scale continued to fall on to the wheel blank as it was being pressed in the forging die.

Most widely used of the present day descaling machines is the chain type descaler. This machine cleans the ends of the wheel blank satis factorily but does not adequately descale the periphery of the blank, whether it is round or rectangular, since minute particles of scale adhere to the peripheral surfaces of the blank after the descaling operation has been completed.

Heretofore, after the ends of the wheel blank had beencleaned by the chain type descaling ma.- chine, the blank was placed, on end, in the forging die and moved into the forging press Where the flattening and initial forming operation was performed. As the blank was being flattened, the scale broke loose from its periphery and fell into the forging die cavity where it remained to be pressed into the forged wheel and cause surface defects which resulted in rejection of the wheel. Rejection was usually necessary since the cavities or pits left in the surface of the wheel by the removal of the hard and brittle pressed-in scale were usually too large to be removed by machining.

The mechanical operation performed by the forging press in flattening the wheel blank is the most efiicient method for removing the scale from the periphery of the blank. At forging temperature the steel wheel blank is in a plastic condition while the scale is inelastic. hard and brittle.

Therefore as the steel flows and deforms under the forging pressure, cleavage occurs at the surface between the steel and the scale which causes the scale to break and spall off into the die. This accumulation of scale in the die would be pressed into the surface of the steel as that itself of the particles of scale which fall from the surface of the wheel block as the wheel is being forged.

Accordingly, it is an object of my invention to provide a forging die having means incorporatedtherein wherein pressure fluid may be introduced to remove fallen scale from the forming cavity of the die as a workpiece is being forged therein.

This and other objects will become apparentafter referring to the following specification and attached drawings, in which:

Figure 1 is a plan view; Figure 2 is a cross-sectional view; and Figure 3 is a cross-sectional view of a modifl fication.

Referring more particularly to the drawings,

reference numeral 2 indicates the main body The diameter of the center bore 6 is slightly greater than the diameter of the pin 8 so as to allow water and fine particles of scale to fall through the bore and not block the action of the stripper pin. The upper end of the main body 2, as shown in Figures 1 and 2, is provided with an annular recess H1 having a concentric cut-out portion l2 in its bottom surrounding the axial bore 6. The cut-out portion l2 forms an annular shoulder l4 spaced from the axial bore 6. An annular ring member [6 is removably disposed in the bottom of the recess Ill spaced from and surrounding the bore 6. The annular ring I6 is provided with an angular upper surface which is adapted to support the workpiece W, as shown in Figure 2, and a cut-away bottom surface which rests partly on the cut-out portion I? of the recess l0 and partly on the annular shoulder M. The outer periphery of the ring it terminates on the shoulder 14 short of the recess wall 18 to form an annular space 20 between the ring and the wall. When the upper die 4 presses the workpiece W into the recess H], the ring l5, together with the grooves and shoulders of the recess it forms the hub, web and rim of the wheel.

The forging die structure thus far described is conventional with the exception of the pressure fluid system of my invention which will now be described-in detail.

An annular groove- 2'2w-is provided in the.:main body 2 in the bottom of the recess l beneath the annular ring IS. A plurality of radial grooves 24 are spaced continuously along thefihm lderld under the ring IS. The radial grooves 2% communicate with the annular groove 22 and-extend; therefrom to the annular space 2El-whichis-formed between th outer periphery of the ring it and the wall It of the recess. Ansaxiallywdirected fluid duct 25 within the body 2 may be connected with the annular groove 22 at two diametrically.

opposed points as shown in Figures 1 and 2. Each of the ,ducts26 is connected with a radially disposed pressure fluid supplyduct 28 .which'extends to .the outer periphery of the body 2,. The outer end of each of the fluidsupply ducts 28 may be provided with a pipetap 30 whereby. itmay be connected to a fluid supplypipe.

In op,eration,,fluid pressure is first admitted into thefluid-supplyducts 28 in sufficient quantities to insure discharge of the fluid from the grocvesi-t. into the space 20. Although any suitable pres- SlllBrflllld maybe used, lhave found it convenient and preferable to use compressed air. Afterthe air pressure has been turned on, the wheel blank W is placed in the recess of the die in the customary manner. and upper die 4 is actuated to initiatethe forging'ofthe :wheel. As the upper die 4,;pressesdown onthe workpiece W, it tends to fdeform it and scale is brokenloose from its surface. As the particles of scale fall, the air streamissuing from the radial grooves 24 picks up. theparticlesand blows them-from the die recess. Th continuous air blast insures'that no falling scale will remaindn the cavity 20 of the die block 2 to be pressed into the. surface of the Wheel as it is formed.

The wheel is removed from the die after-itvis formed and immediatelythereafterthe die. is filled With-water which is immediately blown out by the air ,blast and the die is ready to ,receive. another blank.

Although I:have found it preferable to provide two ducts Y28 and 26, it will be understood that this'numbermay be Varied-fromone to agreater number if desired. Also, it willbe noted that the air supply duct 28, may beconnected directly with the annular groove 22 if desired.

,Ihave found itnecessary to provide additional air outlets in addition to the radial grooves .24 in the cas of dies used ,for forging. the larger sizerailroad car wheels. Where such larger-size wheels arebeing formed, I have found it expedi-r ent ,toinclude .a series of spaced ,vertical,pas-,

sages 32 extending from the groove 22 through the annular ring 16. These vertical air passages are of little use in the forging of small size wheels since they become covered by the spreading metal of the workpiece in a short time after forging is commenced. However, in the case of larger wheels, they are effective in disposing of the great amount of scale .which-fallsfrpm the periphery of the larger workpiece as it-'-is.;being pressed.

While one embodiment of my invention has been shown and described, it will be apparent that Qtheradaptations and modifications may be made without departing from the scope of the followmac eims.

lplaim:

l. A forgingdie for forming a wheel having a humweb ,andrrini from a blank workpiece which comprises a main body portion having an axial bore therethrough and an annular recess in one end thereof, a stripper pin slidably fitted in said bore, the diameter of saidbore being slightly larger than the diameterof said pin, the bottom of saidrecessbeing providedwith a concentric cut-out portion surrounding said axial bore vt0 form an annular shoulder spaced fromthe bore, an annular ring removably disposedin the cutout portion of a said recess spaced from said axial bore, said ring having an angularly shaped .upper surface adapted to-support saidblankworkpiece and .a cut-away bottom surface adapted to rest partlyon the bottom of said cut-.outportion and partly. on said annular shoulder, the outer periphery; of said ring terminating short of the wall of said recess to formanannular space between the ring and the wall, said ring being adapted to cooperate. with said recess to form thehub, web and rimof awheel when a blank workpiece is pressed in said recess, saidmain body having an annulargroove :adjacentthe bottom of said recess beneath said annularring, and a plurality. of spacedradial grooves extending from said annulargroove to saidspace'between said ring and the wall of the recess, said main bodyhaving at least-onepressurefiuid duct connected with said annular groove at onev end and with a source of pressure fluid at its other end for, supplying pressure fluid to said annular space through said annular groove and said radial grooves.

2. Aforging-dieas defined inclaim l.cha rac terized by a plurality of .spacedpressure fluid passages extending axially throughsaid, ring from said annular groove.

References Cited in the file ofthis patent U T STATES ATE S Number "Name Date 1,140,681 Hunt et al May 25, 1915 1,150,439 Zwiker- Aug. 1'7, 1915 1,792,224 Johnson- Feb. 10, 1931 2,305,803 Bayer Dec. 22, 1942 

